Reversible Reactions

is a reaction in which reactants form products and the product(s) can then react or decompose to form reactants. Eg Haber process N₂ + 3H2(g)⇌ 2NH₃

• it can be dynamic or static equilibria
• Dynamic equilibrium is when the rate of forward reaction is equal to rate of reverse reaction
• concentration of all reactants and products remain constant.
• it is achieved only in a closed system ie a system that doesnt allow matter to enter or leave.

Le Chatelier’s principle

if the conditions of an equilibrium are changed, the position of equilibrium moves to oppose the change.

Factors which affect the composition of equilibrium

Temperature

Increasing temperature favours endothermic process and decreasing temperature favours exothermic process.

Pressure

It only affects the position of gaseous systems. when pressure is increased, equilibrium moves to the side with fewer gas molecules /volume and vice versa is true.

Concentration

Decreasing reactant concentration or increasing product conentration, equilibrium moves to left side(backward reaction). and increasing reactant concentration or decreasing product concentration equilibrium moves to forward reaction(right side)

Catalyst

Catalyst is a substance that can increase the rate of a reaction itself remains unchanged at the end of the reaction it catalyses It only alter the position of equilibrium by speeding both forward and backward reactions.